Mechanical WW Continued Adventures of Hairspring Failures (Elgin Bumper)

Dante Sudilovsky

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Oct 21, 2015
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Sorry for the very very lengthy post!

My last NAWCC post from about half a year ago was about an Elgin Bumper with a bungled hairspring...despite amazing, clear advice from everyone on this forum (and a lot of progress on technique, etc.), I did not succeed in bringing that hairspring back to life. I am at college now and only have time for watchmaking very occasionally...and my skills get very very rusty, to say the least.

I got another movement, rinse and repeat (cleaned, etc and all ready to go when lo and behold, the hairspring is out of true). This one appeared to have a fine hairspring when I got it so I have no clue how it is possibly out of true now (and out of true it is). I certainly know how incredibly, incredibly, incredibly delicate these alloy hairsprings are on Elgin Bumpers, but my God I can't stand it anymore (I am about as careful with the balance or around the balance as I can be...I really don't know how this keeps happening). I just want a working bumper without issues.

So, great people of NAWCC, I present my next challenge of hairspring which I will almost certainly fail but will try nonetheless. My whole watchmaking "career" at this point seems to be doing battle with hairsprings and nothing else.

Cut to the chase:

Out of true in the flat, that much is quite obvious. Runs with okay amplitude FD (220-270ish degrees before oiling of escapement) and with poorer amplitude FU (180-220 degrees). It appears in FU that the outer coil is rubbing on the regulator pins, reducing the amplitude. The pictures attached provide some clues of what the issue is.

I've had this problem many times before with this vintage of Elgin movement (running poorly either FD or FU due to hairspring issues) and I find it incredibly, incredibly frustrating to be at this juncture once again. The hairspring stud is slightly untrue which I have adjusted several times (getting it pretty much perfectly flat) to no avail.

It seems to me that there is some sort of a bend before the stud that is taking it out of true, but this is just speculation.

Where should I look to correct this issue? Given my many many experiences trying to fix something like this, I am skeptical of my abilities, but thanks nonetheless. Who knows? Maybe its an easy fix :)

IMG_3489.JPG IMG_3483.JPG IMG_3474.JPG IMG_3491.JPG
 

Jim Haney

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You can relax Dante, that is how it is made. It is called a Breguet Overcoil, You can Google it for a detailed explanation.
 

gmorse

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Hi Dante,

It is indeed a Breguet overcoil, but it shouldn't be quite that shape. I think the arrowed point is where it's bent down too much towards the rest of the spring; the portion from there to the stud should be parallel with the spring.

IMG_3491_edit.jpg

Have you access to the Chicago School of Watchmaking document? if so, lesson 18 section 381 will be helpful.

Regards,

Graham
 

Dante Sudilovsky

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Oct 21, 2015
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Hi Dante,

It is indeed a Breguet overcoil, but it shouldn't be quite that shape. I think the arrowed point is where it's bent down too much towards the rest of the spring; the portion from there to the stud should be parallel with the spring.

View attachment 546371

Have you access to the Chicago School of Watchmaking document? if so, lesson 18 section 381 will be helpful.

Regards,

Graham

Thanks Graham! I do have the CSOW document; that lesson is very helpful and I will read it thoroughly. I think you definitely have the right idea regarding where the issue is.

After looking at the coil closely, it appears to me that it is bent a bit further behind where you highlighted (its quite difficult to see in the pictures I have attached) and I have to make the coil parallel by bending "forward" (toward the inside of the hairspring) at this location. The stud starts to bend upwards away from the hairspring.

However, I almost certainly need to remove the hairspring from the balance to even attempt this operation and I will get a closer look then.

Fingers crossed!
IMG_3507.JPG IMG_3504.JPG IMG_3506.JPG
 

gmorse

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Hi Dante,

However, I almost certainly need to remove the hairspring from the balance to even attempt this operation and I will get a closer look then.
Yes, definitely, the balance spring will have to be removed in order to manipulate it safely. Also, when the stud is attached, its weight can give a false impression and if you don't want to unpin it, holding the spring on a balance tack, (or similar, such as a smoothing broach), so that it's vertical can give you a better idea of what's wrong.

If you bring the overcoil parallel to the rest of the spring you may have to correct the angle of the stud with the spring.

Regards,

Graham
 

GeneJockey

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To me, the stud looks to be tipped backwards. That is, the top should be dead level, but it's high at the pointy end. Clamped into the stud hole that will lift up the regulator sweep as well as the main coils on that side. Notice how high in the regulator gate the terminal coil is sitting.
 

Dante Sudilovsky

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Oct 21, 2015
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Hi Dante,



Yes, definitely, the balance spring will have to be removed in order to manipulate it safely. Also, when the stud is attached, its weight can give a false impression and if you don't want to unpin it, holding the spring on a balance tack, (or similar, such as a smoothing broach), so that it's vertical can give you a better idea of what's wrong.

If you bring the overcoil parallel to the rest of the spring you may have to correct the angle of the stud with the spring.

Regards,

Graham
The results are in: andddd I think (?) you were right about the location. When it is on the balance tack with the stud facing down, the break from parallel appears to be where you had marked originally. But when its in the tack with the stud up it appears to break from parallel where I had thought it was wrong.

Which one is the correct place to bend? It's a bit hard to communicate over the awful pictures, but with the stud facing up, the overcoil appears to go down towards to spring (going below parallel) before going back up near the stud (and going above parallel)

Thanks again,
Dante

IMG_3516.JPG IMG_3523.JPG IMG_3525.JPG IMG_3511.JPG
 

Dante Sudilovsky

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the way to level and circle the first coil of a balance spring is to mount it in the balance bridge. Center the collet over the jewel hole and level the spring using the underside of the bridge as the datum. Circle the overcoil using the regulator as the reference.

Dewey
Thanks for the great advice Dewey! I did what what you said and can certainly see the scope of the issue; also the collet is not currently true to the jewel hole so I am not sure which issue I should "try" to tackle first, trying to make the overcoil parallel or attempting to center it (how does one go about that? I know at one point I knew how to do it, barely, but I seem to have forgotten this knowledge to college...)

I have done nothing so far as I am very very reticent about this hairspring based on my myriad, awful experiences with similar vintage Elgin WW hairpprings. And I really don't want to repeat my past failures

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Dante Sudilovsky

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Oct 21, 2015
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Incredibly, I made a very small adjustment to the hairspring and got the outercoil level, remounted it on the balance, and the watch is running with good amplitude in both DU and DD! Oiled and running for 24 hours before putting on a timing machine. Fingers crossed that it keeps okay time (doesn't really need to be stellar, I just want a working watch).




After that, I have a bit of ambition to work on other hairspring projects now, including this Hamilton 986A which needed/needs quite a bit of work. I managed to get the outercoil level after many hours of finagling but in the process the collet is not even close to being centered over the jewel hole when mounted in the balance cock. The outercoil is also not in between the pins (far away from being close)

(rather than making a whole new thread for this hairspring project)

I looked through my literature for a simple explanation on how centering is done, but couldn't find anything. Could someone point me to a resource (or explain the process) of centering the hairspring!

Thanks

IMG_3834.JPG
 
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Skutt50

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It looks like your problem is located to where the hairspring leaves the stud. Some manipulation there so the hairspring fits inbetween the regulator pins and you just might be redy to play!
 
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Rob P.

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It looks like in your last pic that the HS leaves the stud at a sharp angle instead of leaving straight out of the stud and curving counterclockwise (in the pic) toward the pins on the same arc that the regulator uses.

If you straighten the HS at the stud, it will move the HS collet in a direction toward the regulator pins (Left in the pic) but the collet will still be off to the side of the jewel. Get the overcoil resting without strain between the pins first, then deal with centering the collet.

To center the HS over the jewel, you'll need to bend the HS where the overcoil leaves the outer coils to go on top of the HS. To move the stud closer to the center of the HS l suspect that the area on the overcoil between 7 and 6 in the pic will need reshaped. This will move the collet over the jewels and center it.

Don't bend anywhere near the pins unless that arc needs adjusted. Get the HS coming straight out of the stud and in between the pins first, then center the collet by tweaking the overcoil between 7 and 6 to curl and uncurl as necessary. Fair warning, the sharp bend at the stud may not change without breaking the HS.

Hopefully that doesn't happen but if it does, you can fix that by repinning the HS shorter and then adding mass to the balance to bring it to time. Unless you add mass, it will run fast. You can add timing washers or additional timing screws for that. You will have to poise the balance afterward (without the HS installed) and then reinstall the HS and test for beat. I have done this and it works perfectly.

I made a tool just for HS's. It's a pair of brass tweezers that I flattened the tips on, then bent the tips inward so when squeezed one tip rests on top of the other. I filed the outsides of flattened areas so they were wedge shaped and put a notch in the tips. To use: From underneath the balance, put the tips under the HS collet and squeeze them together. The notches will allow the tips to pass on either side of the staff while the wedge shape pops the collet off its seat. There is almost zero risk of damaging the HS coils because you're not digging under them from the top along the balance arms with a screwdriver or other tool.
 

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